WO2010131422A1 - Image decoding apparatus, integrated circuit, image decoding method, and image decoding system - Google Patents

Abstract

When a motion vector of a co-located macroblock corresponding to a w-th macroblock is necessary for calculating the motion vector of the w-th macroblock, a transfer unit (130A) transfers the motion vector of the co-located macroblock from an external memory (200) to a buffer (124A). Further, when the motion vector of the co-located macroblock corresponding to the w-th macroblock is not necessary for calculating the motion vector of the w-th macroblock, the transfer unit (130A) does not transfer the motion vector of the co-located macroblock corresponding to the w-th macroblock from the external memory (200) to the buffer (124A).

Description

Image decoding apparatus, integrated circuit, image decoding method, and image decoding system

The present invention relates to an image decoding device, an integrated circuit, an image decoding method, and an image decoding system that sequentially decode a plurality of macroblocks constituting an encoded picture in a predetermined order.

In recent years, with the development of multimedia applications, it has become common to handle content such as moving images, still images, audio, and text in a unified manner. At this time, by digitizing all the contents, the contents can be handled uniformly. However, since a digitized image has an enormous amount of data, a moving image information compression technique is indispensable for storage and transmission.

On the other hand, in order to interoperate compressed video data, standardization of compression technology is also important. Hereinafter, the standard of the moving image compression technique is referred to as a moving image compression standard. Examples of the video compression standard include H.264 of ITU-T (International Telecommunication Union, Telecommunication Standardization Sector). 261, H.H. 263. The moving image compression standards include ISO / IEC (International Standards Organization, International Electrotechnical Commission) MPEG (Moving Picture Experts Group) -1, MPEG2, MPEG4, and the like. In addition, the moving image compression standard includes JVT (Joint Video で Team) H.264, which is a combination of ITU-T and MPEG. H.264 / AVC (MPEG4-AVC).

In such a moving image compression standard, one picture is divided into blocks having a predetermined number of pixels (luminance component: 16 pixels × 16 pixels), and decoding processing or encoding processing is performed in units of the blocks. This block as a processing unit is called a macro block.

Depending on the moving image compression technique, one macroblock is further divided into sub-blocks (luminance components: 8 pixels × 8 pixels) of a predetermined number of pixels, and the decoding method or the encoding method is switched in units of the sub-blocks. It is possible. A sub-block that is a unit of processing is called a sub-macro block. Hereinafter, the macroblock or the sub macroblock is collectively referred to as a macroblock.

In general, an important process of moving image compression coding is motion compensation inter-plane prediction in which the amount of information is compressed by reducing redundancy in a time direction in a plurality of consecutive pictures (screens) constituting a moving image. . In the following, a picture that is referred to in coding of a picture to be coded is referred to as a reference picture.

In motion compensation inter-frame prediction, a prediction image is generated by detecting how much the macroblock in the encoding target picture has moved in which direction in the reference picture, and the obtained prediction image and the encoding target picture are obtained. This is a technique for performing encoding on the difference value. The reference picture is a picture in front of or behind the encoding target picture in display order.

Information indicating how much the macroblock in the encoding target picture has moved in which direction in the reference picture is called a motion vector.

A picture that is subjected to intra prediction encoding without using a reference picture is called an I picture. A picture that is subjected to motion compensation inter-frame prediction coding by referring to only one reference picture is called a P picture. A picture for which motion compensation interframe predictive coding is performed with reference to two reference pictures at the same time is called a B picture.

The reference picture can be specified for each macro block. In the encoded bitstream, the reference picture before the encoding target picture in the display order is referred to as a first reference picture. In the encoded bitstream, a reference picture after the encoding target picture is referred to as a second reference picture in display order.

When encoding a B picture, macroblocks constituting the B picture may be encoded in an encoding mode called “direct mode”. The direct mode is an encoding method (encoding mode) in which a motion vector is calculated for each macroblock using a motion vector of another macroblock encoded in the past without encoding a motion vector. .

Hereinafter, a picture to be referred to for calculating a motion vector of a macroblock encoded in the direct mode is referred to as a co-located picture. In the following, in a co-located picture, a macro block located at the same spatial position as a macro block to be encoded is referred to as a co-located macro block.

Specifically, when the macroblock is encoded in the direct mode, the motion vector of the macroblock is calculated using the motion vector of the co-located macroblock.

A conventional process for decoding a macroblock encoded in the direct mode will be described with reference to FIG.

First, as a premise, in preparation for future decoding of macroblocks encoded in direct mode, In H.264 / AVC, when each macroblock in a picture is sequentially decoded, a certain amount of motion vector of each decoded macroblock is stored.

For example, H. According to one H.264 / AVC specification, motion vectors of up to 32 pictures are stored. If one picture is composed of 8160 macroblocks, it is necessary to store motion vectors of a total of 261120 macroblocks.

[To store such a large number of motion vectors in the image decoding apparatus, the capacity of a normal buffer is insufficient, which is not realistic. Therefore, it is general to store the decoded motion vector of each macroblock in a memory such as a DRAM (Dynamic Random Access Memory) outside the image decoding apparatus that performs decoding.

In the following, a macro block may be written as MB. In the following, the motion vector may be expressed as mv.

Here, as shown in FIG. 14, in the MB decoding process, when a macroblock of a B picture is decoded, first, the macroblock type indicated in the header of the macroblock is referred to, and the macroblock is encoded in the direct mode. It is determined whether or not it has been converted (S3000).

When the encoding is performed in the direct mode, a DMA (Direct Memory Access) instruction for acquiring a motion vector of another macro block to be referenced from an external memory is transmitted to a DMA controller (not shown) (S3001). Then, by the motion vector calculation process in step S3002, the motion vector of the macroblock is calculated using the motion vector transferred from the external memory.

However, in the conventional method as shown in FIG. 14, after it is determined that the macroblock is encoded in the direct mode (S3000), the external memory is accessed (S3001), and other necessary elements are required. A motion vector of the macroblock is obtained.

That is, since it is necessary to transfer the motion vector from the external memory to the image decoding apparatus, a waiting time is required as shown by the arrow in FIG. 14, and as a result, the time required to decode the macroblock of the B picture There is a problem that T becomes long.

As a technique for solving this problem, for example, there is a moving picture decoding apparatus disclosed in Patent Document 1. Hereinafter, a conventional image decoding apparatus in Patent Document 1 will be described with reference to FIG.

In the following, the co-located macroblock corresponding to the s (integer greater than or equal to 1) th macroblock is referred to as the sth co-located macroblock. The sth co-located macroblock is a macroblock corresponding to the motion vector used when calculating the motion vector of the sth macroblock.

For example, when s is “n + 1”, the co-located macroblock corresponding to the (n + 1) th macroblock is referred to as the (n + 1) th co-located macroblock.

15, MB (n) header processing refers to processing performed with reference to the header of the nth macroblock. The MB (n) decoding process is a process for decoding the nth macroblock. The motion vector calculation (n) indicates a process for calculating the motion vector of the nth macroblock.

Also, the transfer instruction # (n + 1) transmission indicates a process in which a transfer instruction for transferring the motion vector of the (n + 1) th co-located macroblock to the buffer is transmitted. In addition, mv # (n + 1) transfer indicates processing in which the motion vector of the (n + 1) th co-located macroblock is stored in the buffer by being transferred to the buffer.

In FIG. 15, the case where mvCol is not required is a case where the macro block next to the macro block to be processed is not encoded in the direct mode. The case where mvCol is necessary is a case where the macro block next to the macro block to be processed is encoded in the direct mode. Times T1 and T2 are times required for decoding the corresponding macroblock.

As shown in FIG. 15, the image decoding apparatus in Patent Document 1 decodes the nth macroblock (S4000) and transfers the motion vector of the (n + 1) th co-located macroblock to the buffer (S4001). Are executed in parallel.

Thus, when the (n + 1) th macroblock is encoded in the direct mode, when the (n + 1) th macroblock is decoded at the time (period) T2, the n + 1th co-block immediately stored in the buffer is decoded. A motion vector can be calculated using the motion vector of the located macroblock (S4002).

As a result, the time T2 required to decode the (n + 1) th macroblock is shortened. This parallel processing is similarly performed for the nth, n + 1th, n + 2th,..., (N + x) th macroblocks. The (n + x) th macroblock is the last macroblock included in the stream. Therefore, the same effect is obtained for any macroblock.

Thus, by obtaining the motion vector in advance, it is possible to eliminate the influence on the calculation performance even if the access latency to the external memory is large.

Japanese Patent No. 4106070

However, in the conventional image decoding apparatus, the motion vector of the co-located macroblock is always transferred from the external memory to the buffer regardless of whether or not the macroblock to be decoded is encoded in the direct mode. Therefore, the conventional image decoding apparatus has a problem that unnecessary memory access to the external memory occurs when the decoding target macroblock is not encoded in the direct mode.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an image decoding device, an integrated circuit, and an image decoding that can reduce unnecessary memory access to an external memory. A method and an image decoding system are provided.

In order to solve the above-described problem, an image decoding apparatus according to an aspect of the present invention sequentially decodes a plurality of macroblocks constituting an encoded picture in a predetermined order. The image decoding apparatus includes a transfer unit that performs data communication with an external memory that stores a motion vector of a co-located macroblock corresponding to each macroblock, a buffer, and a first decoding that sequentially decodes the plurality of macroblocks Encoded determination information corresponding to the w (w ≧ v + 1) th macroblock before the decoding of the vth (an integer greater than or equal to 1) th macroblock by the first decoding unit is completed. Second decoding at least determination information for determining whether or not a motion vector of a co-located macroblock corresponding to the wth macroblock is necessary for calculating a motion vector of the wth macroblock. And a co-located macroblock corresponding to the w-th macroblock from the decoding unit and the decoded determination information Motion vector and a determination unit for determining whether it is necessary to calculate the motion vector of the w-th macroblock. When the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, the transfer unit may determine the coth corresponding to the wth macroblock. -The motion vector of the located macroblock is transferred from the external memory to the buffer, and the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock. If not, the motion vector of the co-located macroblock corresponding to the w-th macroblock is not transferred from the external memory to the buffer.

That is, when the motion vector of the co-located macroblock corresponding to the w-th macroblock is necessary for calculating the motion vector of the w-th macroblock, the transfer unit performs co-corresponding to the w-th macroblock. The motion vector of the located macroblock is transferred from the external memory to the buffer. In addition, when the motion vector of the co-located macroblock corresponding to the wth macroblock is not necessary for calculating the motion vector of the wth macroblock, the transfer unit may correspond to the co-located macroblock corresponding to the wth macroblock. The motion vector of the macroblock is not transferred from the external memory to the buffer.

That is, when the motion vector of the co-located macroblock corresponding to the wth macroblock is not necessary for calculating the motion vector of the wth macroblock, the transfer unit may perform the co-located macroblock corresponding to the wth macroblock. The motion vector of the macroblock is not transferred from the external memory to the buffer.

Therefore, unnecessary memory access to the external memory can be reduced.

Preferably, the image decoding apparatus further includes the buffer when the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock. A calculation unit that calculates a motion vector of the w-th macroblock using a motion vector of a co-located macroblock corresponding to the w-th macroblock transferred to the w-th macroblock, and the transfer unit includes the calculated The motion vector of the wth macroblock is transferred to the external memory.

In addition, preferably, the transfer unit, when the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, During the period when the block is being decoded, the motion vector of the co-located macroblock corresponding to the wth macroblock is transferred from the external memory to the buffer, and the co− corresponding to the wth macroblock is transferred. If the motion vector of the located macroblock is not necessary for calculating the motion vector of the wth macroblock, the co-corresponding to the wth macroblock in the period during which the vth macroblock is being decoded. The motion vector of the located macroblock is Kigaibu not transferred from the memory to the buffer.

Also preferably, the second decoding unit decodes only the determination information.

Also preferably, the second decoding unit transmits the decoded determination information to the first decoding unit.

Also preferably, the first decoding unit decodes a part of the w-th macroblock other than the determination information decoded by the second decoding unit.

Also preferably, the determination information indicates whether or not the w-th macroblock is encoded in the direct mode.

Also preferably, the determination information indicates whether or not the w-th macroblock is a skipped macroblock.

Also preferably, the determination information indicates whether or not the w-th macroblock is an inter macroblock.

Also preferably, each of the plurality of macroblocks is H.264. It is a macroblock encoded according to H.264 / AVC.

An integrated circuit according to another aspect of the present invention sequentially decodes a plurality of macroblocks constituting an encoded picture in a predetermined order. An integrated circuit includes a transfer unit that performs data communication with an external memory that stores a motion vector of a co-located macroblock corresponding to each macroblock, a buffer, and a first decoding unit that sequentially decodes the plurality of macroblocks Encoded determination information corresponding to the w (w ≧ v + 1) -th macroblock before decoding of the v-th (an integer greater than or equal to 1) -th macroblock by the first decoding unit, Second decoding for decoding at least determination information for determining whether or not a motion vector of a co-located macroblock corresponding to the wth macroblock is necessary for calculating a motion vector of the wth macroblock Section and the decoded determination information, the operation of the co-located macroblock corresponding to the w-th macroblock Vector and a determination unit for determining whether it is necessary to calculate the motion vector of the w-th macroblock. When the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, the transfer unit may determine the coth corresponding to the wth macroblock. -The motion vector of the located macroblock is transferred from the external memory to the buffer, and the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock. If not, the motion vector of the co-located macroblock corresponding to the w-th macroblock is not transferred from the external memory to the buffer.

An image decoding method according to still another aspect of the present invention is performed by an image decoding apparatus that sequentially decodes a plurality of macroblocks constituting an encoded picture in a predetermined order. The image decoding apparatus sequentially decodes a plurality of macroblocks, a transfer unit that performs data communication with an external memory that stores a motion vector of a co-located macroblock corresponding to each macroblock, a buffer, and the plurality of macroblocks. The encoded decision information corresponding to the w (w ≧ v + 1) -th macroblock before the decoding of the v-th (an integer greater than or equal to 1) -th macroblock by the decoding unit and the first decoding unit is completed. Thus, at least decoding information for determining whether or not the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock is decoded. 2 decoding part. The image decoding method determines whether or not a motion vector of a co-located macroblock corresponding to the w-th macroblock is necessary to calculate a motion vector of the w-th macroblock from the decoded determination information And when the transfer unit needs a motion vector of a co-located macroblock corresponding to the wth macroblock to calculate a motion vector of the wth macroblock, Transferring a motion vector of a co-located macroblock corresponding to the macroblock from the external memory to the buffer, wherein the transfer unit moves the motion of the co-located macroblock corresponding to the w-th macroblock The vector is the motion vector of the wth macroblock If not required to leave, the motion vector of the co-located macroblock corresponding to the w-th macroblock is not transferred from the external memory to the buffer.

An image decoding system according to still another aspect of the present invention includes an image decoding device that sequentially decodes a plurality of macroblocks constituting an encoded picture in a predetermined order, and an external memory. The external memory stores a motion vector of a co-located macroblock corresponding to each macroblock, and the image decoding device includes a transfer unit that performs data communication with the external memory, a buffer, and the plurality of A first decoding unit that sequentially decodes macroblocks and a w (w ≧ v + 1) th macroblock before decoding the v (integer greater than or equal to 1) th macroblock by the first decoding unit It is determined whether the motion vector of the co-located macroblock corresponding to the w th macroblock is necessary for calculating the motion vector of the w th macroblock. A second decoding unit that at least decodes determination information for decoding, and c corresponding to the w-th macroblock from the decoded determination information A determining unit that determines whether or not the motion vector of the located macroblock is necessary for calculating the motion vector of the w-th macroblock, and the transfer unit includes a co corresponding to the w-th macroblock -If the motion vector of the located macroblock is necessary for calculating the motion vector of the wth macroblock, the motion vector of the co-located macroblock corresponding to the wth macroblock is transferred from the external memory to the buffer. If the motion vector of the co-located macroblock corresponding to the wth macroblock is not necessary for calculating the motion vector of the wth macroblock, the co-located macroblock corresponding to the wth macroblock is The motion vector of the macroblock Not transferred to the buffer from the part memory.

In the present invention, all or some of a plurality of constituent elements constituting such an image decoding device may be realized as a system LSI (Large Scale Integration).

Further, the present invention may be realized as an image decoding method in which the operation of a characteristic component included in the image decoding apparatus is a step. Further, the present invention may be realized as a program that causes a computer to execute each step included in such an image decoding method. Further, the present invention may be realized as a computer-readable recording medium that stores such a program. The program may be distributed via a transmission medium such as the Internet.

According to the present invention, unnecessary memory access to the external memory can be reduced.

FIG. 1 is a block diagram showing a configuration of an image decoding system according to Embodiment 1 of the present invention. FIG. 2 is a flowchart of decoding processing according to Embodiment 1 of the present invention. FIG. 3 is a diagram for explaining processing of the image decoding apparatus according to Embodiment 1 of the present invention. FIG. 4 is a flowchart of decoding process A in Embodiment 2 of the present invention. FIG. 5 is a block diagram showing the configuration of the image decoding system. FIG. 6 is a block diagram showing a characteristic functional configuration of the image decoding apparatus. FIG. 7 is an overall configuration diagram of a content supply system that implements a content distribution service according to the third embodiment. FIG. 8 is an overall configuration diagram of the digital broadcasting system according to the third embodiment. FIG. 9 is a block diagram illustrating a configuration example of a television in Embodiment 3. FIG. 10 is a block diagram illustrating a configuration example of an information reproducing / recording unit that reads and writes information from and on a recording medium that is an optical disk. FIG. 11 is a diagram illustrating a structure example of a recording medium that is an optical disk. FIG. 12 is a configuration diagram showing an integrated circuit for realizing the image decoding process. FIG. 13 is a configuration diagram illustrating a configuration example of an integrated circuit that implements image decoding processing. FIG. 14 is a timing chart showing a conventional decoding process. FIG. 15 is a diagram for explaining processing of a conventional image decoding apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an image decoding system 1000 according to Embodiment 1 of the present invention.

1, the image decoding system 1000 includes an image decoding device 100, an external memory 200, a storage medium 300, and a receiving unit 400.

The external memory 200 is connected to the image decoding device 100. The external memory 200 is a writable memory such as a DRAM used as a work area. The external memory 200 temporarily stores data necessary for the image decoding apparatus 100 to execute a decoding process described later.

In the following, moving image data encoded according to the moving image compression standard is referred to as a stream. The video compression standard is H.264. H.264 / AVC (MPEG4-AVC). That is, the stream is moving image data that is variable-length encoded. The stream includes a plurality of macro blocks constituting each encoded picture corresponding to a moving image.

The video compression standard is H.264. H.264 / AVC, MPEG4, MPEG2, MPEG-1, H.264 263, H.M. 261 etc. may be sufficient.

The storage medium 300 is a large-capacity storage medium such as an HDD (Hard Disk Drive). The storage medium 300 stores a stream. The stream is, for example, a stream obtained by recording a television program.

The receiving unit 400 is a digital tuner or the like. The receiving unit 400 receives a stream. The stream is, for example, a stream as a broadcast wave transmitted from a broadcast station, a stream downloaded from the Internet, or the like.

The image decoding apparatus 100 is an apparatus or an integrated circuit that performs stream decoding. The external memory 200 stores a stream received from the storage medium 300 or the receiving unit 400. The image decoding device 100 receives a stream stored in the external memory 200 and decodes the stream.

The image decoding apparatus 100 includes a first decoding unit 111, a second transfer instruction unit 120, a second decoding unit 121, a determination unit 122, an mv transfer instruction unit 123, an mv holding memory 124, and an mv calculation unit 131. An mv transfer instruction unit 132, a reference image transfer instruction unit 133, an inverse orthogonal transform unit 151, an inverse quantization unit 152, an in-plane prediction processing unit 142, a motion compensation processing unit 141, and a predicted image selection unit. 143, a decoded image synthesis unit 161, a deblock filter processing unit 162, a decoded image transfer instruction unit 163, and a DMA controller 130.

The DMA controller 130 is a transfer unit that performs data communication with the external memory 200.

The second transfer instruction unit 120 transmits an instruction for transferring the stream stored in the external memory 200 to the second decoding unit 121 to the DMA controller 130.

The second decoding unit 121 decodes only the header of the macroblock, details of which will be described later. The header indicates the macro block type. The second decoding unit 121 transmits the macroblock type to the determination unit 122.

The determination unit 122 receives the macroblock type transmitted by the second decoding unit 121. Then, the determination unit 122 determines whether or not the macro block is encoded in the direct mode by referring to the macro block type.

In the present embodiment, processing when the direct mode is the time direct mode will be described.

Although details will be described later, the determination unit 122 transmits a vector acquisition instruction for acquiring a motion vector of a co-located macroblock to the mv transfer instruction unit 123 when the macroblock is encoded in the direct mode.

Although details will be described later, the mv transfer instruction unit 123 receives the vector acquisition instruction from the determination unit 122 to transfer the motion vector of the co-located macroblock stored in the external memory 200 to the mv holding memory 124. Process.

The mv holding memory 124 is a buffer for temporarily storing data. The mv holding memory 124 has a capacity capable of storing at least one motion vector of a co-located macroblock. Although details will be described later, the mv holding memory 124 temporarily stores the motion vector of the co-located macroblock transmitted from the DMA controller 130.

Although the details will be described later, the first decoding unit 111 performs variable-length decoding on the macroblock to obtain the header of the macroblock and the pixel residual frequency component. The first decoding unit 111 sequentially decodes a plurality of macroblocks constituting each encoded picture included in the stream in a predetermined order. For example, each of the plurality of macroblocks is H.264. It is a macroblock encoded according to H.264 / AVC.

Here, it is assumed that the first decoding unit 111 decodes the vth (an integer greater than or equal to 1) -th macroblock. In this case, the second decoding unit 121 performs processing on the w (w ≧ v + 1) -th macroblock.

Although the details will be described later, the mv calculation unit 131 calculates a motion vector by a different method depending on the type of the macroblock.

The mv transfer instruction unit 132 transmits a vector storage instruction for storing the motion vector calculated by the mv calculation unit 131 in the external memory 200 to the DMA controller 130.

The reference image transfer instruction unit 133 receives a reference image transfer instruction stored in the external memory 200 for transferring a reference image based on the motion vector calculated by the mv calculation unit 131 to the motion compensation processing unit 141 described later. Transmit to the DMA controller 130.

The inverse orthogonal transform unit 151 calculates a pixel residual component by performing an inverse orthogonal transform on the pixel residual frequency component transmitted from the first decoding unit 111.

The inverse quantization unit 152 obtains a pixel residual value by performing inverse quantization on the pixel residual component calculated by the inverse orthogonal transform unit 151.

In the following, a macroblock encoded in a mode that does not require motion compensation is referred to as an intra macroblock. In the following, a macroblock encoded in a mode that requires motion compensation is referred to as an inter macroblock.

The in-plane prediction processing unit 142 generates a predicted image by performing in-plane prediction when the processing target macroblock is an intra macroblock. The in-plane prediction processing unit 142 transmits the generated predicted image to the predicted image selection unit 143.

When the macroblock to be processed is an inter macroblock, the motion compensation processing unit 141 performs motion compensation intra prediction using the motion vector received from the mv calculation unit 131 and the reference image received from the DMA controller 130. By performing this, a predicted image is generated.

The motion compensation processing unit 141 transmits the generated predicted image to the predicted image selection unit 143.

When the macroblock is an inter macroblock, the predicted image selection unit 143 transmits the predicted image received from the motion compensation processing unit 141 to a decoded image synthesis unit 161 described later. Also, when the macroblock is an intra macroblock, the predicted image selection unit 143 transmits the predicted image received from the in-plane prediction processing unit 142 to the decoded image synthesis unit 161 described later.

The decoded image synthesis unit 161 generates a decoded image by adding the predicted image received from the predicted image selection unit 143 and the pixel residual value received from the inverse quantization unit 152.

The deblock filter processing unit 162 performs deblock filter processing on the decoded image received from the decoded image synthesis unit 161.

The decoded image transfer instruction unit 163 performs a process for storing the decoded image subjected to the deblocking filter processing in the external memory 200, as will be described in detail later.

Next, processing performed by the image decoding system 1000 (hereinafter referred to as decoding processing) will be described. Here, it is assumed that the encoded moving image data (stream) is stored in the external memory 200. The stream includes a plurality of macroblocks constituting each encoded picture corresponding to a moving image. Further, it is assumed that the external memory 200 stores a motion vector of a co-located macroblock corresponding to each of a plurality of macroblocks constituting an encoded picture.

FIG. 2 is a flowchart of the decryption process.

As shown in FIG. 2, in the image decoding apparatus 100, first, a stream transfer process is executed (S101). The stream transfer process is a process performed independently of other processes.

In the stream transfer process, the second transfer instruction unit 120 transmits to the DMA controller 130 a stream transfer instruction for causing the DMA controller 130 to transfer the stream stored in the external memory 200 to the second decoding unit 121. To do.

When receiving the stream transfer instruction, the DMA controller 130 reads the stream from the external memory 200 and transfers the stream to the second decoding unit 121.

Then, the second decoding unit 121 acquires the nth and n + 1th macroblocks from the received stream (S102).

The second decoding unit 121 identifies a skipped macroblock by decoding a part of slice data including the nth and n + 1th macroblocks when acquiring the nth and n + 1th macroblocks. Information to be performed (hereinafter referred to as skip information).

Note that the macroblocks acquired by the second decoding unit 121 are not limited to the nth and n + 1th macroblocks. For example, the macroblock acquired by the second decoding unit 121 may be the nth and n + p (an integer greater than or equal to 2) th macroblock.

The second decoding unit 121 decodes only the header of the (n + 1) th macroblock. Accordingly, the second decoding unit 121 acquires the header of the (n + 1) th macroblock (S120). The acquired header indicates a macro block type, block information, and the like.

This macro block type indicates the encoding mode of the corresponding macro block. The encoding mode is, for example, a direct mode. The block information is information indicating whether the corresponding macro block is an inter macro block or an intra macro block.

And the 2nd decoding part 121 transmits the above-mentioned skip information as determination information, and the macroblock type and block information as determination information to the determination part 122. FIG.

Here, it is assumed that the first decoding unit 111 decodes the vth (an integer greater than or equal to 1) -th macroblock. In this case, as described above, the second decoding unit 121 performs processing on the w (w ≧ v + 1) -th macroblock. In this case, the determination information is encoded information corresponding to the w-th macroblock.

The determination information is information for determining whether or not the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock.

That is, the second decoding unit 121 decodes only the header of the (n + 1) th macroblock as determination information by the process of step S120. Further, as described above, the second decoding unit 121 decodes the skip information as the determination information that is a part of the encoded slice data.

In step S121, the second decoding unit 121 transmits the n-th macroblock of the acquired n-th and n + 1-th macroblocks and the decoded determination information to the first decoding unit 111. The decoded determination information is the above-described skip information and the header of the (n + 1) th macroblock. The header indicates a macro block type, block information, and the like.

Thereby, the first decoding unit 111 acquires the n-th macroblock and the determination information (skip information, macroblock header) by receiving (S110).

The determination unit 122 determines whether or not the (n + 1) th macroblock is a skip target. Specifically, the determination unit 122 determines whether or not the skip information as the received determination information indicates that the (n + 1) th macroblock is a skipped macroblock (S122). That is, the determination information indicates whether or not the w-th macroblock is a skipped macroblock.

If YES in step S122, the process proceeds to step S124. On the other hand, if NO in step S122, the process proceeds to step S123.

When the received skip information as the determination information indicates that the n + 1-th macroblock is a skipped macroblock (YES in S122), the determination unit 122 performs the process of step S124.

In step S123, the determination unit 122 refers to the macroblock type as determination information transmitted by the second decoding unit 121, and determines whether or not the n + 1-th macroblock is encoded in the direct mode. The macro block type indicates the encoding mode of the corresponding macro block. The encoding mode is, for example, a direct mode. That is, the determination information indicates whether or not the w-th macroblock is encoded in the direct mode.

If YES in step S123, the process proceeds to step S124. On the other hand, if NO in step S123, the process proceeds to step S154 described later.

That is, in the processes of steps S122 and S123, the determination unit 122 calculates the motion vector of the co-located macroblock corresponding to the wth macroblock from the decoded determination information. This is a process for determining whether or not it is necessary.

In step S124, the determination unit 122 transmits a vector acquisition instruction for acquiring the motion vector of the co-located macroblock corresponding to the (n + 1) th macroblock to the mv transfer instruction unit 123. The co-located macroblock corresponding to the (n + 1) th macroblock is an (n + 1) th co-located macroblock.

The mv transfer instruction unit 123 performs a process for acquiring the motion vector of the (n + 1) th co-located macroblock according to the received vector acquisition instruction.

Specifically, the mv transfer instruction unit 123 sends a vector transfer instruction for transferring the motion vector of the (n + 1) th co-located macroblock stored in the external memory 200 to the mv holding memory 124. Send to.

When receiving the vector transfer instruction, the DMA controller 130 reads the motion vector of the (n + 1) th co-located macroblock from the external memory 200 and stores the motion vector of the (n + 1) th co-located macroblock in the mv holding memory 124. Forward to. As a result, the motion vector of the (n + 1) th co-located macroblock is stored in the mv holding memory 124.

That is, when the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, the DMA controller 130 serving as the transfer unit performs the wth macroblock. The motion vector of the co-located macroblock corresponding to the block is transferred from the external memory 200 to the mv holding memory 124 as a buffer.

On the other hand, if NO in step S122 and NO in step S123, that is, if the (n + 1) th macroblock is not a skipped macroblock and the (n + 1) th macroblock is not encoded in the direct mode, mv The transfer instruction unit 123 does nothing. If the (n + 1) th macroblock is not a skipped macroblock and the (n + 1) th macroblock is not encoded in the direct mode, the motion vector of the (n + 1) th co-located macroblock is the n + 1th macroblock motion vector. This is a case where it is not necessary to calculate a motion vector.

That is, the DMA controller 130 as the transfer unit determines that the motion vector of the co-located macroblock corresponding to the wth macroblock is not necessary for calculating the motion vector of the wth macroblock. The motion vector of the corresponding co-located macroblock is not transferred from the external memory 200 to the mv holding memory 124 as a buffer.

In parallel with the processes in steps S121 to S124, the processes in steps S111 to S114 are performed.

In step S111, the first decoding unit 111 executes MB decoding processing. The MB decoding process is a process performed independently of other processes. Then, the process proceeds to step S112.

In the MB decoding process, the first decoding unit 111 decodes the acquired nth macroblock. If the header of the nth macroblock has already been decoded by the process of step S120, in the MB decoding process, the first decoding unit 111 decodes a part other than the header of the nth macroblock. . That is, the 1st decoding part 111 decodes parts other than the header as determination information decoded by the 2nd decoding part 121 among wth macroblocks.

When the decoding of the nth macroblock ends, the MB decoding process ends.

By the MB decoding process, the first decoding unit 111 acquires a pixel residual frequency component.

Note that it is assumed that the first decoding unit 111 has acquired the header of the nth macroblock as the determination information by performing the process of the previous step S121. The previous processing in step S121 is processing in which n is replaced with n−1 in the description of processing in step S121.

Then, the first decoding unit 111 transmits the pixel residual frequency component to the inverse orthogonal transform unit 151. In addition, the first decoding unit 111 transmits the header of the nth macroblock to the in-plane prediction processing unit 142.

In step S112, the first decoding unit 111 refers to the header of the nth macroblock as the acquired determination information. Then, the first decoding unit 111 determines whether the nth macroblock is an inter macroblock or an intra macroblock based on the referenced header. That is, the first decoding unit 111 determines whether or not the nth macroblock is an inter macroblock.

If the nth macroblock is an inter macroblock (YES in S112), the process proceeds to step S113.

In step S113, the first decoding unit 111 determines whether or not the nth macroblock is a skip target. Specifically, the first decoding unit 111 determines whether or not the skip information as the received determination information indicates that the nth macroblock is a skipped macroblock.

If YES in step S113, the process proceeds to step S115A. On the other hand, if NO at step S113, the process proceeds to step S114.

In step S114, the first decoding unit 111 refers to the macroblock type indicated by the header of the nth macroblock as the acquired determination information, so that the nth macroblock is encoded in the direct mode. Determine whether.

Here, it is assumed that the processing of the previous steps S102 to S124 has already been performed. The previous processing in steps S102 to S124 is processing in which n is replaced with n-1 in the description of the processing in steps S102 to S124 described above. In this case, it is assumed that the motion vector of the n-th co-located macroblock is stored in the mv holding memory 124 by the previous processing of step S124.

In step S115A, the mv calculation unit 131 calculates the motion vector of the nth macroblock using the motion vector of the nth co-located macroblock stored in the mv holding memory 124. Then, the mv calculation unit 131 transmits the calculated motion vector to the mv transfer instruction unit 132, the reference image transfer instruction unit 133, and the motion compensation processing unit 141.

On the other hand, if NO in step S113 and NO in step S114, that is, it is determined that the nth macroblock is not a skipped macroblock and the nth macroblock is not encoded in the direct mode. If YES, step S115B is performed.

In step S115B, the mv calculation unit 131 calculates a motion vector using the motion vector difference information included in the header of the nth macroblock.

The mv calculation unit 131 transmits the calculated motion vector to the mv transfer instruction unit 132, the reference image transfer instruction unit 133, and the motion compensation processing unit 141.

The mv transfer instruction unit 132 transmits a vector storage instruction for storing the motion vector calculated in step S115A or step S115B in the external memory 200 to the DMA controller 130 together with the calculated motion vector.

When the DMA controller 130 receives the motion vector and the vector storage instruction, the DMA controller 130 associates the motion vector with the spatial position information in the picture of the nth macroblock and transfers it to the external memory 200 (S131). As a result, the motion vector and the spatial position information in the picture of the nth macroblock are stored in the external memory 200 in association with each other.

Then, the reference image transfer instruction unit 133 issues a reference image transfer instruction for causing the motion compensation processing unit 141 to transfer the reference image based on the motion vector transmitted from the mv calculation unit 131 and stored in the external memory 200. The data is transmitted to the DMA controller 130 (S132).

When receiving the reference image transfer instruction, the DMA controller 130 reads the instructed reference image from the external memory 200 and transfers the reference image to the motion compensation processing unit 141.

The motion compensation processing unit 141 performs motion compensation processing (S133). In the motion compensation processing, the motion compensation processing unit 141 generates a predicted image by performing motion compensation inter-surface prediction using the motion vector received from the mv calculation unit 131 and the reference image received from the DMA controller 130. To do. Then, the motion compensation processing unit 141 transmits the generated predicted image to the predicted image selection unit 143.

The predicted image selection unit 143 transmits the predicted image received from the motion compensation processing unit 141 to the decoded image synthesis unit 161 when the nth macroblock is an inter macroblock.

The inverse orthogonal transform unit 151 performs an inverse orthogonal transform process (S134). In the inverse orthogonal transform process, the inverse orthogonal transform unit 151 calculates a pixel residual component by performing an inverse orthogonal transform on the pixel residual frequency component transmitted from the first decoding unit 111. Then, the inverse orthogonal transform unit 151 transmits the pixel residual component to the inverse quantization unit 152.

The inverse quantization unit 152 performs an inverse quantization process (S135). In the inverse quantization process, the inverse quantization unit 152 obtains a pixel residual value by performing inverse quantization on the pixel residual component received from the inverse orthogonal transform unit 151. Then, the inverse quantization unit 152 transmits the pixel residual value to the decoded image synthesis unit 161.

On the other hand, if NO in step S112, that is, if the nth macroblock is an intra macroblock, the mv calculation unit 131 sets the value of the motion vector of the nth macroblock to 0 (step S140). ).

The mv transfer instruction unit 132 transmits a vector storage instruction for storing the motion vector of the nth macroblock in the external memory 200 to the DMA controller 130.

When the DMA controller 130 receives the vector storage instruction, the DMA controller 130 associates the motion vector with the spatial position information in the picture of the n-th macroblock and transfers it to the external memory 200 (S141). As a result, the external memory 200 stores the motion vector and spatial position information in the picture of the nth macroblock in association with each other.

The in-plane prediction processing unit 142 performs in-plane prediction processing (S142). In the in-plane prediction process, the in-plane prediction processing unit 142 generates a predicted image from the peripheral image of the nth macroblock, and transmits the generated predicted image to the predicted image selection unit 143.

The predicted image selection unit 143 transmits the predicted image received from the in-plane prediction processing unit 142 to the decoded image synthesis unit 161 when the nth macroblock is an intra macroblock.

The inverse orthogonal transform unit 151 performs an inverse orthogonal transform process (S144). In the inverse orthogonal transform process, the inverse orthogonal transform unit 151 calculates a pixel residual value by performing an inverse orthogonal transform on the pixel residual frequency component transmitted from the first decoding unit 111. Then, the inverse orthogonal transform unit 151 transmits the pixel residual component to the inverse quantization unit 152.

The inverse quantization unit 152 performs an inverse quantization process (S145). In the inverse quantization process, the inverse quantization unit 152 obtains a pixel residual value by performing inverse quantization on the pixel residual value output from the inverse orthogonal transform unit 151. Then, the inverse quantization unit 152 transmits the pixel residual value to the decoded image synthesis unit 161.

As described above, when the n-th macroblock is an intra macroblock, the predicted image selection unit 143 transmits the predicted image received from the in-plane prediction processing unit 142 to the decoded image synthesis unit 161.

As described above, when the n-th macroblock is an inter macroblock, the predicted image selection unit 143 transmits the predicted image received from the motion compensation processing unit 141 to the decoded image synthesis unit 161.

In addition, the decoded image synthesis unit 161 receives the pixel residual value transmitted by the inverse quantization unit 152 by the processing of step S135 or step S145.

The decoded image synthesis unit 161 performs a decoded image synthesis process (S151). In the decoded image synthesis process, the decoded image synthesis unit 161 generates a decoded image by adding the received pixel residual value and the predicted image. Then, the decoded image synthesis unit 161 transmits the generated decoded image to the deblock filter processing unit 162.

The deblock filter processing unit 162 performs deblock filter processing on the decoded image received from the decoded image synthesis unit 161 (S152). Here, the deblocking filter process is a filter process using a deblocking filter. Then, the deblock filter processing unit 162 transmits the decoded image on which the deblock filter process has been performed to the decoded image transfer instruction unit 163.

The decoded image transfer instruction unit 163 performs a decoded image storage process (S153). In the decoded image storage process, the decoded image transfer instruction unit 163 transmits a decoded image storage instruction for storing the received decoded image in the external memory 200 to the DMA controller 130 together with the decoded image.

When the DMA controller 130 receives the decoded image storage instruction, the DMA controller 130 stores the received decoded image in the external memory 200.

Then, the value of n is incremented by 1 (S154), and the process of step S102 is performed again.

The processes in steps S102 to S124 and the processes in steps S110 to S114 described below are the same as the processes in which n is replaced with n + 1 in the above description, and thus detailed description will not be repeated. A brief description is given below.

The second decoding unit 121 acquires the (n + 1) th and (n + 2) th macroblocks by the process of step S102.

The second decoding unit 121 acquires the header of the (n + 2) th macroblock by the process of step S120.

The second decoding unit 121 transmits the (n + 1) th macroblock and the decoded determination information to the first decoding unit 111 by the process of step S121. The decoded determination information is skip information and the header of the (n + 2) th macroblock. Thereby, the 1st decoding part 111 is acquired by receiving the (n + 1) th macroblock and the determination information (skip information, the header of the (n + 2) th macroblock) (S110).

If YES in step S122 or YES in step S123, the process of step S124 is performed.

The motion vector of the (n + 2) th co-located macroblock is transferred to the mv holding memory 124 by the process of step S124. As a result, the motion vector of the (n + 2) th co-located macroblock is stored in the mv holding memory 124.

In parallel with the processes in steps S121 to S124, the processes in steps S111 to S114 are performed.

The first decoding unit 111 decodes the (n + 1) th macroblock by the MB decoding process executed in the process of step S111.

Then, after the process of step S112, if YES in step S113 or YES in step S114, the process of step S115A is performed. Here, if YES in step S113 or YES in step S114, the n + 1-th macroblock is a skipped macroblock or the n + 1-th macroblock is encoded in the direct mode.

When the (n + 1) th macroblock is a skipped macroblock, or when the (n + 1) th macroblock is encoded in the direct mode, the motion vector of the (n + 1) th co-located macroblock is n + 1th. This is a case necessary for calculating the motion vector of the macroblock.

By the process of step S115A, the mv calculation unit 131 calculates the motion vector of the (n + 1) th macroblock using the motion vector of the (n + 1) th co-located macroblock stored in the mv holding memory 124.

That is, when the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, the mv calculation unit 131 stores the mv holding memory 124 as a buffer. The motion vector of the wth macroblock is calculated using the motion vector of the co-located macroblock corresponding to the transferred wth macroblock.

Note that the processing in steps S131 to S135, the processing in steps S140 to S145, and the processing in steps S151 to S153 are the same as the processing in which n is replaced with n + 1 in the above description, and thus detailed description will not be repeated.

Note that the DMA controller 130 as a transfer unit transfers the calculated motion vector of the w-th macroblock to the external memory 200 by the process of step S131.

As described above, according to the present embodiment, when the (n + 1) th macroblock is a skipped macroblock, or when the (n + 1) th macroblock is encoded in the direct mode, the (n + 1) th co-located macroblock is used. Are transferred to the mv holding memory 124. In parallel with the transfer of the motion vector, the decoding process of the nth macroblock is executed.

When the (n + 1) th macroblock is a skipped macroblock, or when the (n + 1) th macroblock is encoded in the direct mode, the motion vector of the (n + 1) th co-located macroblock is the (n + 1) th macroblock. This is a case necessary for calculation of the motion vector.

When the (n + 1) th macroblock is not a skipped macroblock and the (n + 1) th macroblock is not encoded in the direct mode, the motion vector of the (n + 1) th co-located macroblock is the mv holding memory 124. Not transferred to. In this case, only the decoding process of the nth macroblock is executed.

If the (n + 1) th macroblock is not a skipped macroblock and the (n + 1) th macroblock is not encoded in the direct mode, the motion vector of the (n + 1) th co-located macroblock is the same as that of the (n + 1) th macroblock. This is a case where it is not necessary to calculate a motion vector.

Thus, even when the (n + 1) th macroblock is a skipped macroblock or when the (n + 1) th macroblock is encoded in the direct mode, the mv Using the motion vector of the (n + 1) th co-located macroblock stored in the holding memory 124, the motion vector of the nth macroblock can be calculated.

When the (n + 1) th macroblock is not a skipped macroblock and the (n + 1) th macroblock is not encoded in the direct mode, the motion vector of the (n + 1) th co-located macroblock is obtained from the external memory 200. The data is not transferred to the mv holding memory 124 via the DMA controller 130. Therefore, unnecessary memory access to the external memory can be reduced.

Next, the effect of the processing of this embodiment will be described with reference to FIG. 15 showing the processing of the conventional image decoding apparatus. As shown in FIG. 15, in the conventional video decoding device, regardless of whether or not the motion vector of the (n + 1) th co-located macroblock is necessary for calculating the motion vector of the (n + 1) th macroblock, The decoding process of the nth macroblock and the process of transferring the motion vector of the (n + 1) th co-located macroblock to the buffer are executed in parallel.

That is, even when the motion vector of the (n + 1) th co-located macroblock is not necessary for calculating the motion vector of the (n + 1) th macroblock, the motion vector of the (n + 1) th co-located macroblock is transferred from the external memory. The That is, unnecessary memory access to the external memory occurs.

In contrast, the processing of the present embodiment will be described with reference to FIG. The same terms as FIG. 15 shown in FIG. 3 have been described with reference to FIG.

3, MB (n + 1) header processing refers to processing performed by decoding the header of the (n + 1) th macroblock and referring to the header. The MB (n + 1) header process corresponds to the processes in steps S120 to S123.

Also, MB (n) header processing refers to processing performed with reference to the header of the nth macroblock. The MB (n) header process corresponds to the processes in steps S111 to S114. The MB (n) decoding process is a process for decoding the nth macroblock. The MB (n) decoding process corresponds to step S111.

Also, motion vector calculation (n) indicates processing for calculating the motion vector of the nth macroblock. The transfer instruction # (n + 1) transmission indicates a process in which a transfer instruction for transferring the motion vector of the (n + 1) th co-located macroblock to the mv holding memory 124 is transmitted. Transmission of transfer instruction # (n + 1) corresponds to the process of step S124.

Also, mv # (n + 1) transfer refers to a process in which the motion vector of the (n + 1) th co-located macroblock is stored in the mv holding memory 124 by being transferred to the mv holding memory 124. The mv # (n + 1) transfer corresponds to the process of step S124.

In FIG. 3, the process described on the right side of the “second decoding unit” is a process performed by the second decoding unit 121. The process described on the right side of the “first decoding unit” is a process performed by the first decoding unit 111.

In FIG. 3, when mvCol is not necessary, the motion vector of the co-located macroblock corresponding to the w (for example, n + 1) th macroblock is not necessary for calculating the motion vector of the wth macroblock. Is the case. That is, the case where mvCol is unnecessary is a case where the w-th macroblock is not a skipped macroblock and the w-th macroblock is not encoded in the direct mode.

In FIG. 3, mvCol is necessary when the motion vector of the co-located macroblock corresponding to the w (for example, n + 1) th macroblock is necessary for calculating the motion vector of the wth macroblock. It is the case. That is, the case where mvCol is necessary is a case where the w-th macroblock is a skipped macroblock or a case where the w-th macroblock is encoded in the direct mode.

As shown in FIG. 3, before the decoding of the v (for example, n) -th macroblock by the first decoding unit 111, the second decoding unit 121 sets the w (for example, n + 1) -th macroblock. Corresponding encoded determination information (the header of the w (n + 1) th macroblock) is decoded.

Also, as shown in FIG. 3, the header of the (n + 1) th macroblock is decoded by the second decoding unit 121 by the processing of steps S120 to S123, and processing with reference to the header is performed.

When the (n + 1) th macroblock is a skipped macroblock, or when the (n + 1) th macroblock is encoded in the direct mode, the motion vector of the (n + 1) th co-located macroblock is transferred to the mv holding memory 124. The process to be performed (S124) and the decoding process (S111) of the nth macroblock are executed in parallel. In this case, the process of step S111 and the process of step S115A are executed in parallel.

That is, when the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, the DMA controller 130 serving as the transfer unit During the decoding period, the motion vector of the co-located macroblock corresponding to the w-th macroblock is transferred from the external memory 200 to the mv holding memory 124 as a buffer.

When the (n + 1) th macroblock is not a skipped macroblock and the (n + 1) th macroblock is not encoded in the direct mode, the motion vector of the (n + 1) th co-located macroblock is transferred to the mv holding memory 124. The process (S124) is not executed. In this case, the decoding process (S111) of the nth macroblock is executed. In this case, the process of step S111 and the process of step S115B are executed in parallel.

That is, the DMA controller 130 as the transfer unit decodes the v-th macroblock when the motion vector of the co-located macroblock corresponding to the w-th macroblock is not necessary for calculating the motion vector of the w-th macroblock. In the period when the w-th macroblock is performed, the motion vector of the co-located macroblock corresponding to the w-th macroblock is not transferred from the external memory 200 to the mv holding memory 124 as a buffer.

As a result, when the motion vector of the (n + 1) th co-located macroblock is necessary for calculating the motion vector of the (n + 1) th macroblock, it is immediately stored in the mv holding memory 124 when the (n + 1) th macroblock is decoded. The motion vector can be calculated using the motion vector of the (n + 1) th co-located macroblock.

If the motion vector of the (n + 1) th co-located macroblock is not necessary for calculating the motion vector of the (n + 1) th macroblock, the motion vector of the (n + 1) th co-located macroblock is transferred from the external memory 200 to the DMA controller 130. And not transferred to the mv holding memory 124. Therefore, unnecessary transfer is not performed, and unnecessary memory access to the external memory can be reduced.

This parallel processing is similarly performed for the (n + 2) th, n + 3th,..., N + xth macroblocks. Here, the n + x-th macroblock is the last macroblock included in the stream. Therefore, the same effects as described above can be obtained for any macroblock.

Specifically, even in the case of an image decoding apparatus that needs to store a decoded motion vector in an external memory once due to the buffer capacity restriction in the image decoding apparatus, before starting decoding of a macroblock Only information necessary for determining whether or not a macroblock to be decoded in the future is encoded in the direct mode is decoded in advance.

Then, it is determined whether or not a macroblock to be decoded in the future is encoded in the direct mode. If encoded in the direct mode, the necessary motion vector is transferred from the external memory to the buffer in the image decoding device in advance, and if it is not encoded in the direct mode, the necessary motion vector is transferred. Do not do.

If the macro block is not encoded in the direct mode, the motion vector is not transferred if the macro block is not encoded in the direct mode. If no memory access occurs and the macroblock is encoded in the direct mode, the necessary motion vector is transferred in advance.

Therefore, when a macroblock is encoded in the direct mode, a motion vector can be calculated immediately when decoding the macroblock.

As a result, when the macroblock is encoded in the direct mode, the time required for decoding the macroblock can be shortened and memory access to the external memory can be reduced.

That is, unnecessary memory access to the external memory 200 can be reduced while the macroblock encoded in the direct mode is decoded at high speed.

In the present embodiment, the processing in the case where the direct mode is the time direct mode has been described, but the present invention is not limited to this. Even if the direct mode is the spatial direct mode, this embodiment can be realized. When the direct mode is the spatial direct mode, for example, a motion vector can be calculated by a process similar to the process described in Japanese Patent No. 4106070.

(Embodiment 2)
In the present embodiment, the motion vector of the w-th co-located macroblock is transferred from the external memory 200 to the mv holding memory 124 based on the determination result of whether or not the macroblock to be processed is an inter macroblock.

The image decoding system in the present embodiment is the image decoding system 1000 in FIG. That is, the image decoding apparatus in the present embodiment is the image decoding apparatus 100 in FIG. Therefore, detailed description of each part of the image decoding apparatus 100 will not be repeated.

Next, processing (hereinafter referred to as decoding processing A) performed by the image decoding system 1000 will be described. FIG. 4 is a flowchart of the decoding process A. In FIG. 4, the process with the same step number as the step number of FIG. 2 is the same as the process described in the first embodiment, and therefore detailed description will not be repeated.

Compared with the decoding process of FIG. 2, the decoding process A includes steps S122A instead of step S122, steps S116A instead of step S115A, and steps S123, S113, S114, and S115B. The difference is not done. The rest is the same as the decoding process of FIG.

In step S122A, it is determined whether or not the (n + 1) th macroblock is an inter macroblock using the block information. The block information as the determination information indicates whether or not the w-th macroblock is an inter macroblock.

Specifically, the determination unit 122 determines whether the block information as the determination information received from the second decoding unit 121 indicates that the corresponding macroblock is an inter macroblock.

If YES in step S122A, the process proceeds to step S124. on the other hand. If NO in step S122A, the process proceeds to step S154. The case of YES in step S122A is a case where the motion vector of the co-located macroblock corresponding to the w (for example, n + 1) th macroblock is necessary for calculating the motion vector of the wth macroblock.

Then, the process of step S124 is performed in the same manner as in the first embodiment. As a result, the motion vector of the (n + 1) th co-located macroblock is stored in the mv holding memory 124.

Here, it is assumed that the processing of the previous steps S102 to S124 in FIG. 4 has already been performed. The previous processing of steps S102 to S124 is processing in which n is replaced with n−1 in the description of the processing of steps S102 to S124 described above. In this case, the motion vector of the n-th co-located macroblock is stored in the mv holding memory 124 by the previous processing in step S124. That is, the motion vector of the n-th co-located macroblock is transferred from the external memory 200 to the mv holding memory 124 as a buffer.

If YES in step S112, the process proceeds to step S116A.

In step S116A, the mv calculation unit 131 uses the motion vector difference information included in the header of the nth macroblock and the motion vector of the nth co-located macroblock stored in the mv holding memory 124. , The motion vector of the nth macroblock is calculated.

And the process after step S131 is performed like 1st Embodiment.

As described above, according to the present embodiment, when the macroblock to be decoded next to the macroblock to be decoded is an inter macroblock, the motion vector transfer process of the co-located macroblock is performed. Done. If the macroblock to be decoded next to the macroblock to be decoded is not an inter macroblock, the motion vector transfer process of the co-located macroblock is not performed.

Thereby, the same effect as the first embodiment can be obtained. That is, unnecessary transfer is not performed and unnecessary memory access to the external memory can be reduced.

(Other variations)
In the image decoding device 100 described above, the second decoding unit 121 transmits the acquired n-th macroblock to the first decoding unit 111. That is, the first decoding unit 111 receives a macroblock from the second decoding unit 121, but is not limited thereto. For example, the first decoding unit 111 may acquire a macroblock included in the stream from the external memory 200 via the DMA controller 130.

Hereinafter, an image decoding system 1000A including the image decoding apparatus 100A configured to receive the stream from the external memory 200 by the first decoding unit 111 will be described.

FIG. 5 is a block diagram showing a configuration of the image decoding system 1000A.

5, the image decoding system 1000A is different from the image decoding system 1000 in FIG. 1 in that it includes an image decoding device 100A instead of the image decoding device 100. Since the other configuration of the image decoding apparatus 100A is the same as that of the image decoding apparatus 100A, detailed description will not be repeated.

The image decoding device 100A is different from the image decoding device 100 of FIG. 1 in that it further includes a first transfer instruction unit 110. Since the other configuration of the image decoding device 100A is the same as that of the image decoding device 100, detailed description will not be repeated.

The first transfer instruction unit 110 transmits, to the DMA controller 130, a stream transfer instruction for causing the DMA controller 130 to transfer a stream stored in the external memory 200 to the first decoding unit 111.

When receiving the stream transfer instruction, the DMA controller 130 reads the stream from the external memory 200 and transfers the stream to the first decoding unit 111.

Then, the first decoding unit 111 acquires the nth macroblock from the received stream.

In this case, in the stream transfer process in step S101 of the decoding process of FIG. 2 performed by the image decoding apparatus 100A, each of the first decoding unit 111 and the second decoding unit 121 receives a stream.

In the process of step S102, the first decoding unit 111 and the second decoding unit 121 obtain the nth and n + 1th macroblocks, respectively. Since the processing after step S120 is the same as in the first embodiment, detailed description will not be repeated.

Further, although the image decoding system 1000 has been described based on the embodiment, various modifications can be made to the configuration and operation of this embodiment.

In the above embodiment, in parallel with the decoding process of the macroblock, the macroblock type of the next macroblock is decoded, and if the one macroblock is encoded in the direct mode, the co-located The operation of transferring the motion vector of the macro block to the mv holding memory 124 has been described. However, it is not limited to this.

For example, the capacity of the mv holding memory 124 may be increased, and a plurality of motion vectors corresponding to a plurality of macro-block co-located macroblocks may be transferred together.

For example, when a memory such as a DRAM suitable for continuous data transfer is used as the external memory, if transfer is performed for each motion vector, the burst length may be insufficient and transfer efficiency may be insufficient.

Therefore, when a memory such as a DRAM is used, for example, in parallel with the decoding process of the nth macroblock, the macroblock type decoding of the (n + 1) th macroblock and the (n + 2) th macroblock is executed. .

If any of the (n + 1) th and (n + 2) th macroblocks is encoded in the direct mode, the motion vectors of the (n + 1) th and (n + 2) th macroblock co-located macroblocks are transferred at once. .

When neither the n + 1-th macroblock nor the n + 2-th macroblock is encoded in the direct mode, the motion vector of the co-located macroblock is not transferred.

In this way, by increasing the amount of data transferred in a single DMA transfer, the number of data transfers between the external memory 200 and the mv transfer instruction unit 123 is reduced, and the burst length is increased to improve transfer efficiency. Can be made.

Note that each unit included in the image decoding apparatus 100 of FIG. 1 is typically realized as an LSI that is an integrated circuit. These may be further individually formed into chips such as an integrated circuit and an external memory, or may be realized as a single chip so as to include a part or all of them, that is, realized as a system integrated in a single LSI. .

(Function block diagram)
FIG. 6 is a block diagram illustrating a characteristic functional configuration of the image decoding apparatus 100. That is, FIG. 6 is a block diagram showing the main functions related to the present invention among the functions of the image decoding apparatus 100 shown in FIG. 6 also shows an external memory 200 that is not included in the image decoding device 100 for the sake of explanation.

The image decoding apparatus 100 in FIG. 6 sequentially decodes a plurality of macroblocks constituting an encoded picture in a predetermined order.

As shown in FIG. 6, the image decoding device 100 includes a transfer unit 130A, a buffer 124A, a first decoding unit 111, a second decoding unit 121, and a determination unit 122. The image decoding apparatus 100 in FIG. 6 includes the first decoding unit 111, the second decoding unit 121, and the determination unit 122 described in FIG.

The transfer unit 130A performs data communication with the external memory 200 that stores the motion vector of the co-located macroblock corresponding to each macroblock.

The buffer 124A corresponds to the mv holding memory 124.

The first decoding unit 111 sequentially decodes a plurality of macroblocks.

The second decoding unit 121 decodes at least the determination information before the first decoding unit 111 finishes decoding the vth (an integer greater than or equal to 1) -th macroblock. The determination information is encoded information corresponding to the w (w ≧ v + 1) -th macroblock. The determination information is information for determining whether or not the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock. . The decoded determination information is, for example, the above-described macroblock type, block information, and skip information.

The determination unit 122 determines from the decoded determination information whether the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock. . The determination unit 122 corresponds to the determination unit 122 that performs the processing in steps S122 and S123 in FIG. 2 or the processing in step S122A in FIG.

When the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, the transfer unit 130A determines that the co-located macroblock corresponds to the wth macroblock. The motion vector of the macro block is transferred from the external memory 200 to the buffer 124A. The transfer unit 130A corresponds to the mv transfer instruction unit 123 and the DMA controller 130 that perform the process of step S124 of FIG.

In addition, when the motion vector of the co-located macroblock corresponding to the wth macroblock is not necessary for calculating the motion vector of the wth macroblock, the transfer unit 130A determines that the co−corresponding to the wth macroblock. The motion vector of the located macroblock is not transferred from the external memory 200 to the buffer 124A.

Note that all or part of the transfer unit 130A, the buffer 124A, the first decoding unit 111, the second decoding unit 121, and the determination unit 122 in FIG. 6 are hardware such as an LSI (Large Scale Integration). It may be configured. All or part of the transfer unit 130A, the buffer 124A, the first decoding unit 111, the second decoding unit 121, and the determination unit 122 may be a module of a program executed by a processor such as a CPU.

(Embodiment 3)
By recording a program for realizing the configuration of the image decoding method described in each of the above embodiments on a storage medium, the processing described in each of the above embodiments can be easily performed in an independent computer system. It becomes. The storage medium may be any medium that can record a program, such as a magnetic disk, an optical disk, a magneto-optical disk, an IC card, and a semiconductor memory.

Furthermore, application examples of the image decoding method shown in the above embodiments and a system using the same will be described here.

FIG. 7 is a diagram showing an overall configuration of a content supply system ex100 that realizes a content distribution service. The communication service providing area is divided into desired sizes, and base stations ex106 to ex110, which are fixed radio stations, are installed in each cell.

In this content supply system ex100, devices such as a computer ex111, a PDA (Personal Digital Assistant) ex112, a camera ex113, a mobile phone ex114, and a game machine ex115 are mutually connected via a telephone network ex104 and base stations ex106 to ex110. Connected. Each device is connected to the Internet ex101 via the Internet service provider ex102.

However, the content supply system ex100 is not limited to the configuration shown in FIG. 7 and may be connected by combining any of the elements. Further, each device may be directly connected to the telephone network ex104 without going through the base stations ex106 to ex110 which are fixed wireless stations. In addition, the devices may be directly connected to each other via short-range wireless or the like.

The camera ex113 is a device that can shoot a moving image such as a digital video camera, and the camera ex116 is a device that can shoot a still image and a moving image such as a digital camera. In addition, the mobile phone ex114 is a GSM (Global System for Mobile Communications) method, a CDMA (Code Division Multiple Access) method, a W-CDMA (Wideband-Code Division MultipleL), or a high access rate (L) system. (High Speed Packet Access) type mobile phone, PHS (Personal Handyphone System), etc., which may be either.

In the content supply system ex100, the camera ex113 and the like are connected to the streaming server ex103 through the base station ex109 and the telephone network ex104, thereby enabling live distribution and the like. In live distribution, the content (for example, music live video) captured by the user using the camera ex113 is encoded as described in the above embodiments and transmitted to the streaming server ex103. On the other hand, the streaming server ex103 streams the transmitted content data to the requested client. Examples of the client include a computer ex111, a PDA ex112, a camera ex113, a mobile phone ex114, a game machine ex115, and the like that can decode the encoded data. Each device that has received the distributed data decodes and reproduces the received data.

Note that the encoded processing of the captured data may be performed by the camera ex113, the streaming server ex103 that performs data transmission processing, or may be performed in a shared manner. Similarly, the distributed processing of the distributed data may be performed by the client, the streaming server ex103, or may be performed in a shared manner. In addition to the camera ex113, still images and / or moving image data captured by the camera ex116 may be transmitted to the streaming server ex103 via the computer ex111. The encoding process in this case may be performed by any of the camera ex116, the computer ex111, and the streaming server ex103, or may be performed in a shared manner.

In addition, these encoding processing and decoding processing are generally executed in a computer ex111 and an LSI (Large Scale Integration) ex500 included in each device. The LSI ex500 may be configured as a single chip or a plurality of chips. It should be noted that image encoding software or image decoding software is incorporated into any recording medium (CD-ROM, flexible disk, hard disk, etc.) that can be read by the computer ex111 and the like, and encoding processing or decoding processing is performed using the software. May be performed. Furthermore, when the mobile phone ex114 is equipped with a camera, moving image data acquired by the camera may be transmitted. The moving image data at this time is data encoded by the LSI ex500 included in the mobile phone ex114.

Further, the streaming server ex103 may be a plurality of servers or a plurality of computers, and may process, record, and distribute data in a distributed manner.

As described above, in the content supply system ex100, the encoded data can be received and reproduced by the client. As described above, in the content supply system ex100, the information transmitted by the user can be received, decrypted and reproduced in real time by the client, and even a user who does not have special rights and facilities can realize personal broadcasting.

It should be noted that not only the example of the content supply system ex100 but also at least one of the image decoding devices of the above-described embodiments can be incorporated in the digital broadcast system ex200 as shown in FIG. Specifically, in the broadcasting station ex201, a bit stream of video information is transmitted to a communication or satellite ex202 via radio waves. This bit stream is an encoded bit stream encoded by the image encoding method described in the above embodiments. Receiving this, the broadcasting satellite ex202 transmits a radio wave for broadcasting, and the home antenna ex204 capable of receiving the satellite broadcast receives the radio wave. The received bit stream is decoded and reproduced by a device such as the television (receiver) ex300 or the set top box (STB) ex217.

In addition, the image decoding apparatus described in the above embodiment can be mounted on the playback apparatus ex212 that reads and decodes the bitstream recorded on the recording medium ex214 such as a CD and a DVD that are recording media. In this case, the reproduced video signal is displayed on the monitor ex213.

In addition, the image decoding shown in the above embodiments is also performed on the reader / recorder ex218 that reads and decodes the encoded bitstream recorded on the recording medium ex215 such as DVD and BD, or encodes and writes the video signal on the recording medium ex215. It is possible to implement a device or an image coding device. In this case, the reproduced video signal is displayed on the monitor ex219, and the video signal can be reproduced in another device and system using the recording medium ex215 in which the encoded bitstream is recorded. Further, an image decoding device may be mounted in a set-top box ex217 connected to a cable ex203 for cable television or an antenna ex204 for satellite / terrestrial broadcasting and displayed on the monitor ex219 of the television. At this time, the image decoding apparatus may be incorporated in the television instead of the set top box.

FIG. 9 is a diagram showing a television (receiver) ex300 that uses the image decoding method described in the above embodiments. The television ex300 includes a tuner ex301 that acquires or outputs a bit stream of video information via the antenna ex204 or the cable ex203 that receives the broadcast, and the encoded data that is demodulated or transmitted to the outside. A modulation / demodulation unit ex302 that modulates and a multiplexing / separation unit ex303 that separates demodulated video data and audio data or multiplexes encoded video data and audio data.

Further, the television ex300 decodes each of the audio data and the video data, or encodes each information, an audio signal processing unit ex304, a signal processing unit ex306 including the video signal processing unit ex305, and outputs the decoded audio signal. A speaker ex307 and an output unit ex309 including a display unit ex308 such as a display for displaying the decoded video signal; Furthermore, the television ex300 includes an interface unit ex317 including an operation input unit ex312 that receives an input of a user operation. Furthermore, the television ex300 includes a control unit ex310 that controls each unit in an integrated manner, and a power supply circuit unit ex311 that supplies power to each unit.

In addition to the operation input unit ex312, the interface unit ex317 includes a bridge ex313 connected to an external device such as a reader / recorder ex218, a recording unit ex216 such as an SD card, and an external recording such as a hard disk. A driver ex315 for connecting to a medium, a modem ex316 for connecting to a telephone network, and the like may be included. The recording medium ex216 can record information electrically by using a nonvolatile / volatile semiconductor memory element to be stored.

Each part of the television ex300 is connected to each other via a synchronous bus.

First, a configuration in which the television ex300 decodes and reproduces data acquired from the outside by the antenna ex204 and the like will be described. The television ex300 receives a user operation from the remote controller ex220 or the like, and demultiplexes the video data and audio data demodulated by the modulation / demodulation unit ex302 by the multiplexing / separation unit ex303 based on the control of the control unit ex310 having a CPU or the like. . Furthermore, in the television ex300, the separated audio data is decoded by the audio signal processing unit ex304, and the separated video data is decoded by the video signal processing unit ex305 using the decoding method described in the above embodiments. The decoded audio signal and video signal are output to the outside from the output unit ex309. When outputting, these signals may be temporarily stored in the buffers ex318, ex319, etc. so that the audio signal and the video signal are reproduced in synchronization. The television ex300 may read the encoded bitstream encoded from the recording media ex215 and ex216 such as a magnetic / optical disk and an SD card, not from broadcasting.

Next, a description will be given of a configuration in which the television ex300 encodes an audio signal and a video signal and transmits them to the outside or writes them on a recording medium or the like. The television ex300 receives a user operation from the remote controller ex220 or the like, and encodes an audio signal with the audio signal processing unit ex304 based on the control of the control unit ex310, and converts the video signal with the video signal processing unit ex305. Encoding is performed using the encoding method described in (1). The encoded audio signal and video signal are multiplexed by the multiplexing / demultiplexing unit ex303 and output to the outside. When multiplexing, these signals may be temporarily stored in the buffers ex320, ex321, etc. so that the audio signal and the video signal are synchronized.

It should be noted that a plurality of buffers ex318 to ex321 may be provided as shown in the figure, or one or more buffers may be shared. Further, in addition to the illustrated example, data may be stored in the buffer as a buffer material that prevents system overflow and underflow, for example, between the modulation / demodulation unit ex302 and the multiplexing / demultiplexing unit ex303.

In addition to acquiring audio data and video data from broadcast and recording media, the television ex300 has a configuration for receiving AV input of a microphone and a camera, and even if encoding processing is performed on the data acquired therefrom Good. Here, the television ex300 has been described as a configuration capable of the above-described encoding processing, multiplexing, and external output. However, these processing cannot be performed, and only the above-described reception, decoding processing, and external output are possible. It may be.

When the encoded bitstream is read from or written to the recording medium by the reader / recorder ex218, the decoding process or the encoding process may be performed by either the television ex300 or the reader / recorder ex218, The ex300 and the reader / recorder ex218 may share each other.

As an example, FIG. 10 shows a configuration of the information reproducing / recording unit ex400 when data is read from or written to an optical disk. The information reproducing / recording unit ex400 includes elements ex401 to ex407 described below.

The optical head ex401 writes information by irradiating a laser spot on the recording surface of the recording medium ex215 that is an optical disk, and reads information by detecting reflected light from the recording surface of the recording medium ex215. The modulation recording unit ex402 electrically drives a semiconductor laser built in the optical head ex401 and modulates the laser beam according to the recording data. The reproduction demodulator ex403 amplifies the reproduction signal obtained by electrically detecting the reflected light from the recording surface by the photodetector built in the optical head ex401, separates and demodulates the signal component recorded on the recording medium ex215, and is necessary. To play back information. The buffer ex404 temporarily holds information to be recorded on the recording medium ex215 and information reproduced from the recording medium ex215. The disk motor ex405 rotates the recording medium ex215. The servo control unit ex406 moves the optical head ex401 to a predetermined information track while controlling the rotational drive of the disk motor ex405, and performs a laser spot tracking process.

The system control unit ex407 controls the entire information reproduction / recording unit ex400. In the reading and writing processes described above, the system control unit ex407 uses various types of information held in the buffer ex404, and generates and adds new information as necessary, as well as the modulation recording unit ex402, the reproduction demodulation unit This is realized by recording / reproducing information through the optical head ex401 while operating the ex403 and the servo control unit ex406 in a coordinated manner. The system control unit ex407 includes, for example, a microprocessor, and executes these processes by executing a read / write program.

In the above, the optical head ex401 has been described as irradiating a laser spot, but it may be configured to perform higher-density recording using near-field light.

FIG. 11 shows a schematic diagram of a recording medium ex215 that is an optical disk. Guide grooves (grooves) are formed in a spiral shape on the recording surface of the recording medium ex215, and address information indicating the absolute position on the disc is recorded in advance on the information track ex230 by changing the shape of the groove. This address information includes information for specifying the position of the recording block ex231 which is a unit for recording data, and the recording block is specified by reproducing the information track ex230 and reading the address information in a recording and reproducing apparatus. Can do. Further, the recording medium ex215 includes a data recording area ex233, an inner peripheral area ex232, and an outer peripheral area ex234. The area used for recording the user data is the data recording area ex233, and the inner circumference area ex232 and the outer circumference area ex234 arranged on the inner circumference or outer circumference of the data recording area ex233 are used for specific purposes other than user data recording. Used.

The information reproducing / recording unit ex400 reads / writes encoded audio data, video data, or encoded data obtained by multiplexing these data with respect to the data recording area ex233 of the recording medium ex215.

In the above description, an optical disk such as a single-layer DVD or BD has been described as an example. However, the present invention is not limited to these, and an optical disk having a multilayer structure and capable of recording other than the surface may be used. Also, an optical disc with a multi-dimensional recording / reproducing structure, such as recording information using light of different wavelengths in the same place on the disc, or recording different layers of information from various angles. It may be.

Also, in the digital broadcasting system ex200, the car ex210 having the antenna ex205 can receive data from the satellite ex202 and the like, and the moving image can be reproduced on a display device such as the car navigation ex211 that the car ex210 has. The configuration of the car navigation ex211 may be, for example, the configuration shown in FIG. 9 with the addition of a GPS receiver, and the same may be considered for the computer ex111, the mobile phone ex114, and the like. In addition to the transmission / reception terminal having both an encoder and a decoder, the mobile phone ex114 and the like can be used in three ways: a transmitting terminal having only an encoder and a receiving terminal having only a decoder. The implementation form of can be considered.

As described above, the image encoding method or the image decoding method shown in each of the above embodiments can be used in any of the above-described devices or systems, and by doing so, the effects described in the above embodiments can be obtained. Can be obtained.

Further, the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the present invention.

(Embodiment 4)
In the present embodiment, the image decoding apparatus 100 is realized as an LSI that is typically a semiconductor integrated circuit. A form in which the image decoding apparatus 100 of FIG. 6 is realized as an LSI 2100 is shown in FIG. Each component of the image decoding apparatus 100 is configured on the LSI 2100 shown in FIG.

These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

Furthermore, if integrated circuit technology that replaces LSI emerges as a result of advances in semiconductor technology or other derived technologies, it is naturally also possible to integrate functional blocks using this technology. Biotechnology can be applied as a possibility.

In addition, by combining a semiconductor chip in which the image decoding apparatus according to this embodiment is integrated with a display for drawing an image, a drawing device corresponding to various uses can be configured. The present invention can be used as information drawing means in cellular phones, televisions, digital video recorders, digital video cameras, car navigation systems, and the like. As a display, in addition to a cathode ray tube (CRT), a flat display such as a liquid crystal, a PDP (plasma display panel) and an organic EL, a projection display represented by a projector, and the like can be combined.

Further, the LSI in the present embodiment cooperates with a DRAM (Dynamic Random Access Memory) including a bit stream buffer for storing an encoded stream and a frame memory for storing an image, thereby performing an encoding process or a decoding process. May be performed. Further, the LSI in the present embodiment may be linked with other storage devices such as eDRAM (embedded DRAM), SRAM (Static Random Access Memory), or hard disk instead of DRAM.

(Embodiment 5)
The image decoding apparatus and the image decoding method described in the above embodiments are typically realized by an LSI that is an integrated circuit. As an example, FIG. 13 shows the configuration of an LSI ex500 that is made into one chip. The LSI ex500 includes elements ex502 to ex509 described below, and each element is connected via a bus ex510. The power supply circuit unit ex505 starts up to an operable state by supplying power to each unit when the power supply is in an on state.

For example, when encoding processing is performed, the LSI ex500 receives an AV signal input from the microphone ex117, the camera ex113, and the like by the AV I / Oex 509. The input AV signal is temporarily stored in an external memory ex511 such as SDRAM. The accumulated data is divided into a plurality of times as appropriate according to the processing amount and processing speed, and sent to the signal processing unit ex507. The signal processing unit ex507 performs encoding of an audio signal and / or encoding of a video signal. Here, the encoding process of the video signal is the encoding process described in the above embodiment. The signal processing unit ex507 further performs processing such as multiplexing the encoded audio data and the encoded video data according to circumstances, and outputs the result from the stream I / Oex 504 to the outside. The output bit stream is transmitted to the base station ex107 or written to the recording medium ex215.

Further, for example, when performing the decoding process, the LSI ex500 transmits the encoded data obtained from the base station ex107 or the recording medium ex215 by the stream I / Oex 504 based on the control of the microcomputer (microcomputer) ex502. The encoded data obtained by reading is temporarily stored in the memory ex511 or the like. Based on the control of the microcomputer ex502, the accumulated data is appropriately divided into a plurality of times according to the processing amount and the processing speed and sent to the signal processing unit ex507, where the signal processing unit ex507 decodes the audio data and / or the video data. Decryption is performed. Here, the decoding process of the video signal is the decoding process described in the above embodiments. Further, in some cases, each signal may be temporarily stored in the memory ex511 or the like so that the decoded audio signal and the decoded video signal can be reproduced in synchronization. The decoded output signal is output from the AVI / Oex 509 to the monitor ex219 or the like through the memory ex511 or the like as appropriate. When accessing the memory ex511, the memory controller ex503 is used.

In the above description, the memory ex511 has been described as an external configuration of the LSI ex500. However, a configuration included in the LSI ex500 may be used. The LSI ex500 may be made into one chip or a plurality of chips.

In addition, although it was set as LSI here, it may be called IC, system LSI, super LSI, and ultra LSI depending on the degree of integration.

Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

Furthermore, if integrated circuit technology that replaces LSI emerges as a result of advances in semiconductor technology or other derived technology, it is naturally also possible to integrate functional blocks using this technology. Biotechnology can be applied.

It should be noted that these embodiments are examples, and the present invention is not limited to these embodiments. Unless it deviates from the meaning of this invention, the form which carried out various deformation | transformation which those skilled in the art can think to this embodiment, or the structure constructed | assembled combining the component in different embodiment is also contained in the scope of the present invention. .

Further, all or some of the plurality of constituent elements constituting the image decoding device may be configured by hardware. Further, all or some of the components constituting the image decoding apparatus may be a module of a program executed by a CPU (Central Processing Unit) or the like.

Further, all or some of the plurality of constituent elements constituting the image decoding device may be configured by one system LSI (Large Scale Integration). The system LSI is an ultra-multifunctional LSI manufactured by integrating a plurality of components on one chip. Specifically, a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), etc. It is a computer system comprised including.

Further, the present invention may be realized as an image decoding method in which the operation of a characteristic component included in the image decoding apparatus is a step. Further, the present invention may be realized as a program that causes a computer to execute each step included in such an image decoding method. Further, the present invention may be realized as a computer-readable recording medium that stores such a program. The program may be distributed via a transmission medium such as the Internet.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

The image decoding apparatus according to the present invention is useful for various applications, for example, as an information display device and a photographing system such as a television, a digital video recorder, a car navigation system, a mobile phone, a digital camera, and a digital video camera.

100, 100A Image decoding apparatus 110 First transfer instruction unit 111 First decoding unit 120 Second transfer instruction unit 121 Second decoding unit 122 Determination unit 123 mv transfer instruction unit 124 mv holding memory 124A buffer 130 DMA controller 130A transfer unit 131 mv Calculation unit 132 mv transfer instruction unit 133 Reference image transfer instruction unit 141 Motion compensation processing unit 142 In-plane prediction processing unit 143 Predicted image selection unit 151 Inverse orthogonal transform unit 152 Inverse quantization unit 161 Decoded image synthesis unit 162 Deblock filter processing unit 163 Decoded image transfer instruction unit 200 External memory 300 Storage medium 400 Receiving unit 1000, 1000A Image decoding system 2100 LSI
ex100 Content supply system ex101 Internet ex102 Internet service provider ex103 Streaming server ex104 Telephone network ex106, ex107, ex108, ex109, ex110 Base station ex111 Computer ex112 PDA (Personal Digital Assistant)
ex113, ex116 Camera ex114 Mobile phone ex115 Game machine ex117 Microphone ex200 Digital broadcasting system ex201 Broadcast station ex202 Broadcast satellite (satellite)
ex203 Cable ex204, ex205 Antenna ex210 Car ex211 Car navigation (car navigation system)
ex212 Playback device ex213, ex219 Monitor ex214, ex215, ex216 Recording media ex217 Set-top box (STB)
ex218 reader / recorder ex220 remote controller ex230 information track ex231 recording block ex232 inner circumference area ex233 data recording area ex234 outer circumference area ex300 television (receiver)
ex301 tuner ex302 modulation / demodulation unit ex303 multiplexing / demultiplexing unit ex304 audio signal processing unit ex305 video signal processing unit ex306, ex507 signal processing unit ex307 speaker ex308 display unit ex309 output unit ex311, ex505 power supply circuit unit ex312 operation input unit ex313 bridge ex314 slot Unit ex315 driver ex316 modem ex317 interface unit ex318, ex319, ex320, ex321, ex404 buffer ex400 information reproduction / recording unit ex401 optical head ex402 modulation recording unit ex403 reproduction demodulation unit ex405 disk motor ex406 servo control unit ex407 system control unit ex502 microcomputer (micro Computer)
ex503 Memory controller ex504 Stream I / O
ex509 AV I / O
ex510 bus

Claims (13)

1. An image decoding device that sequentially decodes a plurality of macroblocks constituting an encoded picture in a predetermined order,
   A transfer unit that performs data communication with an external memory that stores a motion vector of a co-located macroblock corresponding to each of the macroblocks;
   A buffer,
   A first decoding unit for sequentially decoding the plurality of macroblocks;
   Before the decoding of the v (an integer greater than or equal to 1) -th macroblock by the first decoding unit is completed, encoded determination information corresponding to the w (w ≧ v + 1) -th macroblock, A second decoding unit for decoding at least determination information for determining whether or not the motion vector of the co-located macroblock corresponding to the th macroblock is necessary for calculating the motion vector of the wth macroblock; ,
   A determination unit that determines from the decoded determination information whether a motion vector of a co-located macroblock corresponding to the wth macroblock is necessary to calculate a motion vector of the wth macroblock; With
   The transfer unit is
   If the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, the co-located macroblock corresponding to the wth macroblock Transferring a motion vector from the external memory to the buffer;
   If the motion vector of the co-located macroblock corresponding to the wth macroblock is not necessary for calculating the motion vector of the wth macroblock, the motion of the co-located macroblock corresponding to the wth macroblock Do not transfer vectors from the external memory to the buffer;
   Image decoding device.
2. The image decoding device further includes:
   When the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, it corresponds to the wth macroblock transferred to the buffer. a calculation unit that calculates a motion vector of the w-th macroblock using a motion vector of the co-located macroblock;
   The transfer unit transfers the calculated motion vector of the w-th macroblock to the external memory;
   The image decoding apparatus according to claim 1.
3. The transfer unit is
   When the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary to calculate the motion vector of the wth macroblock, the vth macroblock is decoded during the period. Transfer a motion vector of a co-located macroblock corresponding to the w th macroblock from the external memory to a buffer;
   When the motion vector of the co-located macroblock corresponding to the wth macroblock is not necessary for calculating the motion vector of the wth macroblock, in the period when the vth macroblock is being decoded, Do not transfer the motion vector of the co-located macroblock corresponding to the wth macroblock from the external memory to the buffer;
   The image decoding apparatus according to claim 1 or 2.
4. The second decoding unit decodes only the determination information;
   The image decoding device according to any one of claims 1 to 3.
5. The second decoding unit transmits the decoded determination information to the first decoding unit.
   The image decoding device according to any one of claims 1 to 4.
6. The first decoding unit decodes a portion of the w-th macroblock other than the determination information decoded by the second decoding unit;
   The image decoding device according to claim 4 or 5.
7. The determination information indicates whether the w-th macroblock is encoded in the direct mode.
   The image decoding device according to any one of claims 1 to 6.
8. The determination information indicates whether or not the w-th macroblock is a skipped macroblock.
   The image decoding device according to any one of claims 1 to 6.
9. The determination information indicates whether the w-th macroblock is an inter macroblock,
   The image decoding device according to any one of claims 1 to 6.
10. Each of the plurality of macroblocks is H.264. A macroblock encoded according to H.264 / AVC.
    The image decoding device according to any one of claims 1 to 9.
11. An integrated circuit that sequentially decodes a plurality of macroblocks constituting an encoded picture in a predetermined order,
    A transfer unit that performs data communication with an external memory that stores a motion vector of a co-located macroblock corresponding to each of the macroblocks;
    A buffer,
    A first decoding unit for sequentially decoding the plurality of macroblocks;
    Before the decoding of the v (an integer greater than or equal to 1) -th macroblock by the first decoding unit is completed, encoded determination information corresponding to the w (w ≧ v + 1) -th macroblock, A second decoding unit for decoding at least determination information for determining whether or not the motion vector of the co-located macroblock corresponding to the th macroblock is necessary for calculating the motion vector of the wth macroblock; ,
    A determination unit that determines from the decoded determination information whether a motion vector of a co-located macroblock corresponding to the wth macroblock is necessary to calculate a motion vector of the wth macroblock; With
    The transfer unit is
    If the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, the co-located macroblock corresponding to the wth macroblock Transferring a motion vector from the external memory to the buffer;
    If the motion vector of the co-located macroblock corresponding to the wth macroblock is not necessary for calculating the motion vector of the wth macroblock, the motion of the co-located macroblock corresponding to the wth macroblock Do not transfer vectors from the external memory to the buffer;
    Integrated circuit.
12. An image decoding method performed by an image decoding apparatus that sequentially decodes a plurality of macroblocks constituting an encoded picture in a predetermined order,
    The image decoding device includes:
    A transfer unit that performs data communication with an external memory that stores a motion vector of a co-located macroblock corresponding to each of the macroblocks;
    A buffer,
    A first decoding unit for sequentially decoding the plurality of macroblocks;
    Before the decoding of the v (an integer greater than or equal to 1) -th macroblock by the first decoding unit is completed, encoded determination information corresponding to the w (w ≧ v + 1) -th macroblock, A second decoding unit for decoding at least determination information for determining whether or not the motion vector of the co-located macroblock corresponding to the th macroblock is necessary for calculating the motion vector of the wth macroblock; With
    The image decoding method includes:
    Determining from the decoded determination information whether a motion vector of a co-located macroblock corresponding to the wth macroblock is necessary for calculating a motion vector of the wth macroblock;
    When the transfer unit needs the motion vector of the co-located macroblock corresponding to the wth macroblock to calculate the motion vector of the wth macroblock, the transfer unit corresponds to the coth corresponding to the wth macroblock. Transferring a motion vector of a located macroblock from the external memory to the buffer;
    When the motion vector of the co-located macroblock corresponding to the w-th macroblock is not necessary for calculating the motion vector of the w-th macroblock, the transfer unit determines that the co-corresponds to the w-th macroblock. do not transfer the motion vector of the located macroblock from the external memory to the buffer;
    Image decoding method.
13. An image decoding system including an image decoding device that sequentially decodes a plurality of macroblocks constituting an encoded picture in a predetermined order, and an external memory,
    The external memory stores a motion vector of a co-located macroblock corresponding to each macroblock;
    The image decoding device includes:
    A transfer unit for data communication with the external memory;
    A buffer,
    A first decoding unit for sequentially decoding the plurality of macroblocks;
    Before the decoding of the v (an integer greater than or equal to 1) -th macroblock by the first decoding unit is completed, encoded determination information corresponding to the w (w ≧ v + 1) -th macroblock, A second decoding unit for decoding at least determination information for determining whether or not the motion vector of the co-located macroblock corresponding to the th macroblock is necessary for calculating the motion vector of the wth macroblock; ,
    A determination unit that determines from the decoded determination information whether a motion vector of a co-located macroblock corresponding to the wth macroblock is necessary to calculate a motion vector of the wth macroblock; With
    The transfer unit is
    If the motion vector of the co-located macroblock corresponding to the wth macroblock is necessary for calculating the motion vector of the wth macroblock, the co-located macroblock corresponding to the wth macroblock Transferring a motion vector from the external memory to the buffer;
    If the motion vector of the co-located macroblock corresponding to the wth macroblock is not necessary for calculating the motion vector of the wth macroblock, the motion of the co-located macroblock corresponding to the wth macroblock Do not transfer vectors from the external memory to the buffer;
    Image decoding system.
    
    

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